Regioregular copolymers and methods for making same

ABSTRACT

Methods for producing regioregular poly(aryl ethynyl)-poly(aryl vinyl) and monomers for preparing the regioregular poly(aryl ethynyl)-poly(aryl vinyl) polymers are described herein. Regioregular poly(aryl ethynyl)-poly(aryl vinyl) are useful for electronics, among other things.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application filing under 35U.S.C. §120 of U.S. patent application Ser. No. 13/811,758, filed Jan.23, 2013, now U.S. Pat. No. 8,937,148, entitled “Regioregular Copolymersand Methods for Making Same,” which in turn claims the benefit of andpriority to U.S. national stage filing under 35 U.S.C. §371 ofInternational Application No. PCT/US2012/054147, filed Sep. 7, 2012 andentitled “Regioregular Copolymers and Methods for Making Same,” thedisclosure of which is incorporated by reference in its entirety and forall purposes.

BACKGROUND

The classes of polymers known as poly(p-phenyleneethynylene)s, or PPEs,and poly(p-phenylenevinylene)s, or PPVs, have found uses as activelayers in light-emitting diodes, “plastic lasers,” lightemitting-electrochemical cells, thin film transistors, and chemicalsensors. Hybrid polyphenylenevinylene-ethynylenes copolymers, or“PPVEs,” having strictly alternating PPE and PPV monomeric units combinethe physical (phase, thermal) behaviour of the PPEs/PPVs with a newclass of optical properties, including enhanced electron affinity. Thismakes PPVEs incredibly promising candidates for use in transistors andother solid-state electronic devices. Their unique electronics can beeasily tuned via the side chains, while retaining the well-understoodsolid-state phase behaviour, X-ray diffraction, and the like of thePPEs. Such PPVE polymers have been used for their charge carriermobility, especially in anthracene-PPVE copolymers, electroluminescentproperties, photovoltaic properties for use in solar cells, and as theactive component in thin film field effect transistors.

Work on poly(thiophene)s has shown that the identity and relativeposition of side chains along a conjugated polymer backbone has a largeimpact on the properties of the resulting polymer. Normal polymerizationmethods incorporate all possible combinations into the backbone,producing an inherently regiorandom polymer. There are steric and (insome cases) electronic “clashes” between side chains which “point”towards each other, twisting the backbone out of planarity withcorresponding effects on the effective conjugation length and overallpolymer crystallinity. This is of great importance, not only for thepoly(thiophene)s but for any rigid-rod conjugated polymer thatexperiences a similar occurrence.

Regioregular materials have higher crystallinity, red-shiftedabsorptions in the optical region, a greater conductivity, and (usually)a smaller band-gap compared to the regiorandom versions of the samepolymer. This has direct and powerful implications on the use of thesematerials for electronic applications. These effects have been studiedin poly(1,4-phenylenevinylene)s and poly(1,4-phenyleneethynylene)s, butnot for PPVEs due primarily to a lack of a valid synthetic route toregioregular PPVEs.

SUMMARY

Embodiments of the invention are generally directed to methods forpreparing regioregular copolymers, monomeric units useful in suchmethods, and methods for preparing these monomeric units. For example,some embodiments include methods for making regioregular arylethynyl-aryl vinyl copolymers that include a compound of Formula IV:

wherein each R^(1a), R^(1b), R^(2a), and R^(2b), independently, isC₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol and n isan integer of 2 or more.

Other embodiments include compounds having the general Formula I:

wherein each R^(1a) and R^(2a) is, independently, C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol and each R⁵ is, independently,C₁-C₂₀ alkyl. Further embodiments include methods for making thecompounds of Formula I, and methods that use such compounds for theproduction of regioregular aryl ethynyl-aryl vinyl copolymers.

Still other embodiments include compounds having the general Formula II:

wherein each R^(1b) and R^(2b) is, independently, C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol; each R³ and R⁴ is,independently, C₁-C₂₀ alkyl; and X is hydroxide, alkoxide, astatine,iodine, bromine, chlorine, or fluorine, triflate (CF₃SO₃ ⁻), mesylate(CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), or besylate (C₆H₅SO₃ ⁻). Furtherembodiments include methods for making the compounds of Formula II, andmethods that use such compounds for the production of regioregularcopolymers.

Yet other embodiments are directed to compounds having the generalFormula III:

wherein each R^(1a), R^(1b), R^(2a), and R^(2b) is, independently,C₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol; and X ishydroxide, alkoxide, astatine, iodine, bromine, chlorine, or fluorine,triflate (CF₃SO₃ ⁻), mesylate (CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), orbesylate (C₆H₅SO₃ ⁻). Further embodiments include methods for making thecompounds of Formula III, and methods that use such compounds for theproduction of regioregular copolymers. Additional embodiments includemethods for making compounds of general Formula III from compounds ofgeneral Formulae I and II.

BRIEF DESCRIPTION OF THE FIGURES

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presentedherein. It will be readily understood that the aspects of the presentdisclosure, as generally described herein and illustrated in theFigures, can be arranged, substituted, combined, separated, and designedin a wide variety of different configurations, all of which areexplicitly contemplated herein.

FIG. 1 is a schematic of a chemical synthesis corresponding to thesynthesis scheme defined herein.

DETAILED DESCRIPTION

Various embodiments are directed to monomeric units that can be used inthe production of polymers as well as methods for making these monomers.Further embodiments are directed to polymers created using thesemonomeric units and methods for making such polymers. The monomericunits, or monomers, can be incorporated into any polymer or type ofpolymer known in the art including various thermoplastic and thermosetresins, and in particular embodiments, the monomers of the invention canbe incorporated into regioregular copolymers.

The monomeric units of various embodiments generally include at leastone aromatic moiety. For example, in some embodiments, the monomericunit may be a silylalkynyl dialkoxyl arylaldehyde such as, but notlimited to, a compound of general Formula I:

where each R^(1a) and R^(2a) can, independently, be C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol and each R⁵ can be C₁-C₂₀alkyl. In other embodiments, the monomeric unit may be a X-substituteddialkoxyl arylphosphonate such as, but not limited to, a compound ofgeneral Formula II:

where each R^(1b) and R^(2b) is, independently, C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol; each R³ and R⁴ is,independently, C₁-C₂₀ alkyl; and X can be, for example, hydroxide,alkoxide, astatine, iodine, bromine, chlorine, or fluorine, triflate(CF₃SO₃ ⁻), mesylate (CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), or besylate(C₆H₅SO₃ ⁻). In still other embodiments, the monomeric unit may be aX-substituted silylalkynyl diarylethene such as, but not limited to, acompound of general Formula III:

where each R^(1a), R^(1b), R^(2a), and R^(2b) can, independently, beC₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol, R⁵ canbe C₁-C₂₀ alkyl, and X can be, for example, hydroxide, alkoxide,astatine, iodine, bromine, chlorine, or fluorine, triflate (CF₃SO₃ ⁻),mesylate (CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), or besylate (C₆H₅SO₃ ⁻).In each of the embodiments, described above, R^(1a) and R^(1b) can bethe same, R^(2a) and R^(2b) can be the same, or R^(1a) and R^(1b) can bethe same and R^(2a) and R^(2b) can be the same, and in some embodiments,R^(1a), R^(1b), R^(2a), and R^(2b) can each be different, or variouscombinations of R^(1a), R^(1b), R^(2a), and R^(2b) can be the same ordifferent.

Without wishing to be bound by theory, the leaving groups X, e.g.hydroxide, alkoxide, astatine, iodine, bromine, chlorine, or fluorine,triflate (CF₃SO₃ ⁻), mesylate (CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), orbesylate (C₆H₅SO₃ ⁻), phosphonate (P(O)OR³OR⁴), aldehyde (CHO), andsilyl (≡C(SiR₅)₃) groups associated with the monomeric units exemplifiedabove may allow these monomeric units to be particularly useful for anynumber of polymerization reactions. Moreover, the arrangement of theseleaving groups provides a means for controlling the arrangement of thesemonomeric units. For example, in certain embodiments, the monomericunits described above, or other compounds having the leaving groupsdescribed above may be used in the preparation of regiospecific orregioregular polymers in reactions that are regioselective. A“regioselective reaction” is a chemical reaction in which one directionof bond making or breaking occurs preferentially over all other possibledirections. The term “regiospecific” or “regiospecific reaction” as usedherein refers to a polymerization reaction that is 100% or nearly 100%regioselective, resulting in a polymer that is exclusively or nearlyexclusively composed of one of several possible isomeric products.Generally, regiospecific is defined as a reaction that results inregioselectivity within the limit of detection. For ¹H NMR, the currentstandard method, about 95% to about 100%, about 97% to about 100%, about98% to about 100%, or about 99% to about 100% of the bonds in aregiospecific polymer will be of one isomeric product. The isomericproducts of regiospecific reactions are referred to as “regioregularpolymers.”

In some embodiments, the monomeric units may be used in regioselectiveor regiospecific reactions that are intended to result in regioregularpolymers. For example, particular embodiments are directed to a methodfor preparing regioregular aryl ethynyl-aryl vinyl copolymers. Ingeneral, such methods may include the steps of providing a silylalkynyldialkoxyl arylaldehyde and a X-substituted dialkoxyl arylphosphonate andcontacting the silylalkynyl dialkoxyl arylaldehyde and the X-substituteddialkoxyl arylphosphonate under conditions that provide for coupling ofthe silylalkynyl dialkoxyl arylaldehyde and the X-substituted dialkoxylarylphosphonate to provide a X-substituted silylalkynyl diarylethene. Inparticular embodiments, the silylalkynyl dialkoxyl arylaldehyde may be acompound of Formula I:

where each R^(1a) and R^(2a) can, independently, be C₁-C₂₀ alkyl, C₂-C₂₀alkene, or C₂-C₂₀ alkyne and each R⁵ can be C₁-C₂₀ alkyl, and in someembodiments, the X-substituted dialkoxyl arylphosphonate comprises acompound of Formula II:

where each R^(1b) and R^(2b) can, independently, be C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol, each R³ and R⁴ can,independently, be C₁-C₂₀ alkyl, and X can be, for example, hydroxide,alkoxide, astatine, iodine, bromine, chlorine, or fluorine, triflate(CF₃SO₃ ⁻), mesylate (CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), or besylate(C₆H₅SO₃ ⁻). In certain embodiments, R^(1a) and R^(1b) can be the sameand R^(2a) and R^(2b) can be the same. In particular embodiments,contacting the silylalkynyl dialkoxyl arylaldehyde and the X-substituteddialkoxyl arylphosphonate under conditions that provide for coupling ofthe silylalkynyl dialkoxyl arylaldehyde and the X-substituted dialkoxylarylphosphonate may include a Horner-Wadsworth-Emmons coupling. TheX-substituted dialkoxyl arylphosphonate may be of any formula and, insome embodiments, may be a compound of Formula III:

where each R^(1a), R^(1b), R^(2a), and R^(2b) can, independently, beC₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol, R⁵ canbe C₁-C₂₀ alkyl, and X can be, for example, hydroxide, alkoxide,astatine, iodine, bromine, chlorine, or fluorine, triflate (CF₃SO₃ ⁻),mesylate (CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), or besylate (C₆H₅SO₃ ⁻).

In some embodiments, such methods may further include the steps ofplacing the X-substituted silylalkynyl diarylethene under conditionsthat allow the silyl moiety to be removed from the X-substitutedsilylalkynyl diarylethene to provide a X-substituted alkynyldiarylethene and placing the X-substituted alkynyl diarylethene underconditions that allow X-substituted alkynyl diarylethenes to be coupledto provide the regioregular aryl ethynyl-aryl vinyl copolymer. Inparticular embodiments, the coupling reaction resulting from placing theX-substituted alkynyl diarylethene under conditions that allow theX-substituted alkynyl diarylethenes to be coupled may be a Sonogashiracoupling.

In embodiments, such as those described above, the resultingregioregular copolymer may be a compound of Formula IV:

where each R^(1a), R^(1b), R^(2a), and R^(2b) can, independently, beC₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol, and ncan be an integer from 2 or more, or in some embodiments, n may be aninteger from 2 to 100. In certain embodiments, R^(1a) and R^(1b) may bethe same and R^(2a) and R^(2b) may be the same, and in particularembodiments, the copolymer of Formula IV can be regioregular.

The method described above may have any number of additional steps, andsuch additional steps may be carried out in any order. For ease ofdescription, FIG. 1 provides a reaction scheme for the synthesis ofvarious regioregular copolymers encompassed by the invention.Intermediate compounds formed during the synthesis are numbered andindividual steps in the synthesis method are identified using letters.As indicated by the superscripts, steps a-f are carried out in thepreparation of both monomeric units corresponding to Formulae I and IIdescribed above, which are identified in the reaction scheme of FIG. 1as compounds 7 and 14 respectively.

In FIG. 1, synthesis of the regioregular aryl ethynyl-aryl vinylcopolymers begins in step a¹, a² by providing a para-substituted arene0, which is exemplified by hydroquinone, and a halogenated C₂-C₂₀ alkyl,C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol. These components arecombined or “contacted” under conditions that allow the para-substitutedarene 0 and the halogenated C₂-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne,or alkylene glycol to react to provide a monoalkoxyl para-substitutedarene 1. In some exemplary embodiments, the para-substituted arene maybe hydroquinone, and in certain embodiments, the monoalkoxylpara-substituted arene 1 produced by this step may be a 4-alkoxyphenol.In particular embodiments, the halogenated C₂-C₂₀ alkyl, C₂-C₂₀ alkene,or C₂-C₂₀ alkyne used in step a¹ may be different from the halogenatedC₂-C₂₀ alkyl, C₂-C₂₀ alkene, or C₂-C₂₀ alkyne used in step a² such thatR^(1a) of intermediate 1 may be different from R^(2b) of intermediate 8.In other embodiments, the halogenated C₂-C₂₀ alkyl, C₂-C₂₀ alkene,C₂-C₂₀ alkyne, or alkylene glycol used in step a¹, a² may be the samesuch that intermediates 1 and 8 will be the same. Steps a¹-f¹ and a²-f²are generally carried out separately; however, in certain embodiments inwhich R^(1a) and R^(2b) are the same, steps a¹-f¹ and a²-f² may becarried out simultaneously in the same reaction vessel.

Attachment of one side chain to the para-substituted arene 0 isgenerally achieved by nucleophilic substitution (S_(N)2), whichtypically produces about 60% to about 70% yield of the monoalkoxylpara-substituted hydroxyarene 1 product. Without wishing to be bound bytheory, based on the different solubilities of para-substituted arene 0,the monoalkoxyl para-substituted hydroxyarene 1, and di-substitutedby-products, the monoalkoxyl para-substituted hydroxyarene 1 can beeasily purified by recrystallization. The size and nature of R¹ and/orR² can vary among embodiments, and may depend on the intended end use ofthe polymer. In embodiments in which R¹ and/or R² are long alkyl chains,recrystallization may result in a white solid.

In step b¹, b², a protecting group may be introduced onto themonoalkoxyl para-substituted hydroxyarene 1, 8, at the remaininghydroxyl in a step that includes contacting a protecting groupcontaining compound and the monoalkoxyl para-substituted hydroxyarene 1,8 under conditions that allow the protecting group containing compoundand the monoalkoxyl para-substituted hydroxyarene 1, 8, to react toprovide the protected monoalkoxyl para-substituted arene 2, 9. Theprotecting group containing compound may be any known protecting groupcontaining compound, and in some embodiments, the protecting group maybe bulky and/or electron withdrawing. For example, in variousembodiments, the protecting group containing compound may be acetyl,benzoyl, benzyl, β-methoxyethoxymethyl ether, dimethoxytrityl,[bis-(4-methoxyphenyl)phenylmethyl], methoxymethyl ether, methoxytrityl[(4-methoxyphenyl)diphenylmethyl], p-methoxybenzyl ether,methylthiomethyl ether, pivaloyl, tetrahydropyranyl, trityltriphenylmethyl, silyl ether, trimethylsilyl ether,tert-butyldimethylsilyl ether, tri-iso-propylsilyloxymethyl ether,tri-iso-propylsilyl ether, ethoxyethyl ether, carbobenzyloxy,p-methoxybenzyl carbonyl, tert-butyloxycarbonyl,9-fluorenylmethyloxycarbonyl, carbamate, p-methoxybenzyl,3,4-dimethoxybenzyl, p-methoxyphenyl, tosyl, sulfonamide, and the likeand combinations thereof. In particular embodiments, the protectinggroup may be a tosyl, and in certain embodiments, protected monoalkoxylpara-substituted arene 2, 9, may be 4-(alkoxy)phenyl 4-protecting group,such as the tosylate (Ts) containing compound, 4-(alkoxy)phenyl4-methylbenzensulfonate, in FIG. 1. In embodiments, in which theprotecting group is a tosylate group, the addition of the protectinggroup may be carried out by combining the monoalkoxyl para-substitutedarene 1, 8, with tosyl chloride (TsCl) in pyridine at room temperature.Without wishing to be bound by theory, a tosylate protecting group isstable to acid, readily cleaved by base, but also presents a stericbarrier towards electrophilic aromatic substitution at thea-substituents on the benzene ring of the monoalkoxyl para-substitutedarene 1, 8.

In various embodiments, a leaving group (X) may be introduced onto thearene of the monoalkoxyl para-substituted arene 2, 9, at a carbonadjacent to the alkoxy substituent, step c¹, c². In various embodiments,the leaving group X can be, for example, hydroxide, alkoxide, astatine,iodine, bromine, chlorine, or fluorine, triflate (CF₃SO₃ ⁻), mesylate(CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), or besylate (C₆H₅SO₃ ⁻). Inexemplary embodiments, the leaving group (X) may consist of iodine.Thus, the method of embodiments may include the step of placing theprotected monoalkoxyl arene 2, 9, under conditions that allow theaddition of a leaving group (X) to the protected monoalkoxyl arene 2, 9,to provide the protected X-substituted monoalkoxyl arene 3, 10. Incertain embodiments, the protected X-substituted monoalkoxyl arene 3,10, may be 3-halogen 4-alkoxyphenyl 1-protecting group, and in someembodiments, the protected X-substituted monoalkoxyl arene 3, 10, may be3-iodo-4-(alkoxy)phenyl 1-methylbenzensulfonate, as illustrated inFIG. 1. Without wishing to be bound by theory, the presence of theprotecting group opposite the alkoxyl group, i.e., at a para position,may reduce or eliminate the possibility of a leaving group (X) beingintroduced onto a carbon adjacent to the protecting group. In someembodiments, introducing a leaving group (X) onto the monoalkoxyl arene2, 9, can be carried out by oxidative iodination in acidic medium whichyields the desired monoiodinated monoalkoxyl arene 3, 10 in good yield.

In various embodiments, the protecting group may be removed after theaddition of a leaving group (X) has been carried out. For example, insome embodiments, the method may include the step of placing theprotected X-substituted monoalkoxyl para-substituted arene 3, 10, underconditions that allow a protecting group to be removed from theprotected X-substituted monoalkoxyl arene 3, 10, to provide theunprotected X-substituted monoalkoxyl hydroxyarene 4, 11. In particularembodiments where the leaving group (X) consists of iodine, a tosylategroup may be removed by a mixture of aqueous sodium hydroxide (NaOH) andt-butanol at reflux, and acidic workup can yield free iodophenol.

A second alkyl, alkene, or alkyne R^(2a), R^(1b) can then be introducedonto the hydroxyl remaining after the protecting group has been removed.In some embodiments, the method may include the step e¹, e² ofcontacting a hydroxylated C₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, oralkylene glycol, and the unprotected X-substituted monoalkoxylhydroxyarene 4, 11, under conditions that allow the hydroxylated C₁-C₂₀alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol and theunprotected X-substituted monoalkoxyl hydroxyarene 4, 11, to react toprovide the unprotected X-substituted dialkoxyl arene 5, 12. In variousembodiments, the alkyl, alkene, alkyne, or alkylene glycol R^(2a),R^(1b) introduced in step e¹, e² may be the same as the alkyl, alkene,alkyne, or alkylene glycol R^(1a), R^(2b) introduced onto thepara-substituted arene 0 in step a¹, a². In certain embodiments, thealkyl, alkene, alkyne, or alkylene glycol R^(2a) introduced in step e¹may be the same alkyl, alkene, or alkyne R^(2b) introduced in step a²,and the alkyl, alkene, alkyne, or alkylene glycol R^(1b) introduced instep e² may be the same alkyl, alkene, alkyne, or alkylene glycol R^(1a)introduced in step a¹. Thus, in some embodiments, the hydroxylatedC₂-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol and thehalogenated C₂-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkyleneglycol may include different C₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne,or alkylene glycol moieties. In particular embodiments, the step ofcontacting in steps e¹ and e² may include a Mitsunobu coupling, and insome embodiments, the Mitsunobu coupling can be carried out using resinbound triphenylphosphine (PPh₃). A Mitsunobu coupling is then used whichmay utilize modified conditions, including resin-bound PPh₃ (to enableeasy purification of the coupled product/regeneration of the resin) aswell as azopyridine instead of diethyl azodicarboxylate (DEAD), whichcan be regenerated and reused. In particular embodiments, the secondside chain attached in this step can be non-identical to R¹ and can betailored to meet the final demands of the polymer.

The methods of various embodiments may further include the step ofintroducing an aldehyde-containing substituent onto the unprotectedX-substituted dialkoxyl arene 5, 12. Such steps can be carried out bycontacting a C₁-C₆ alkoxy C₁-C₆ dihaloalkyl and the unprotectedX-substituted dialkoxyl arene 5, 12 under conditions that allow theC₁-C₆ alkoxy C₁-C₆ dihaloalkyl and the unprotected X-substituteddialkoxyl arene 5, 12 to react to provide the X-substituted dialkoxylarylaldehyde 6, 13. In certain embodiments, the X-substituted dialkoxylarylaldehyde 6, 13 may be a compound of Formula V:

where each R^(1a), R^(1b), R^(2a), and R^(2b) can, independently, beC₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol; and Xcan be, for example, hydroxide, alkoxide, astatine, iodine, bromine,chlorine, or fluorine, triflate (CF₃SO₃ ⁻), mesylate (CH₃SO₃ ⁻),tosylate (CH₃C₆H₄SO₂ ⁻), or besylate (C₆H₅SO₃ ⁻). Without wishing to bebound by theory, the directing effects of the R^(2a) or R^(1b) andR^(1a), or R^(2b) and the leaving group (X) on the benzene cause thealdehyde (CHO) to be positioned opposite, i.e., para, to the leavinggroup (X) under various reaction conditions. For example, in particularembodiments, when the X-substituted dialkoxyl arene 5, 12 may be exposedto a mixture of TiCl₄/CHCl₂OCH₃ dissolved in dichloromethane (CH₂Cl₂) atlow temperatures (−10° C., ice-salt bath) to provide the X-substituteddialkoxyl arylaldehyde 6, 13 having the aldehyde in the proper position.

As discussed above, the synthetic route for silylalkynyl dialkoxylarylaldehyde 7 monomer and the X-substituted dialkoxyl arylphosphonate14 are similar. However, in certain embodiments, the side chainR^(1a,2b) may be first attached to the para-substituted arene 0 firstinstead of R^(2a,1b) to ensure that in the final monomer, similar sidechains are arranged in the proper orientation with respect to each otherand do not become mismatched. This provides the regioregular polymer.Thus steps leading up to intermediate 6 are the same as the stepsleading to intermediate 13, with the exception that now the placement ofthe two side chains are switched.

The preparation of the silyl-containing monomer of Formula I,intermediate 7 in FIG. 1, may proceed by introducing a silyl containinggroup onto the X-substituted dialkoxyl arylaldehyde 6, step g. Forexample, in some embodiments, the method may include contacting asilyl-alkynyl and the X-substituted dialkoxyl arylaldehyde 6 underconditions that allow the silyl-alkynyl and X-substituted dialkoxylarylaldehyde 6 to react to provide the silylalkynyl dialkoxylarylaldehyde 7. The silyl-alkynyl may be any silyl alkynyl group knownin the art including, but not limited to, trimethylsilyl acetylene,tert-butyldimethylsilyl acetylene, tri-iso-propylsilyloxymethylacetylene, or tri-iso-propylsilyl acetylene, and in certain embodiments,the silyl-alkynyl may be tri-iso-propylsilyl acetylene, i.e., TIPS, asexemplified in FIG. 1. Step g, may result in a compound of Formula I:

where each R^(1a) and R^(2a) can, independently, be C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol and each R⁵ can be C₁-C₂₀alkyl. In particular embodiments the monomeric unit 7 resulting fromstep g may be a compound of general Formula Ia:

where R^(1a) and R^(2a) can, independently, be C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol. In particular embodiments,the X-substituted dialkoxyl arylaldehyde 6 can be coupled to oneequivalent of silyl containing compound such as TIPS-acetylene(TIPS=tri-iso-propyl silyl) under palladium-catalyzed couplingconditions to produce a protected alkyne, silylalkynyl dialkoxylarylaldehyde 7. The reaction proceeds quantitatively, and theTIPS-alkyne group is stable to a wide variety of reaction conditions andcan be easily removed to give the bare alkyne.

The phosphonate containing monomer of Formula II, intermediate 14 inFIG. 1, can be produced by introducing a phosphonate group into theX-substituted dialkoxyl arylaldehyde 13, step h. In some embodiments,the method may include the step of contacting a phosphonate containingcompound and the X-substituted dialkoxyl arylaldehyde 13 underconditions that allow the phosphonate containing compound and theX-substituted dialkoxyl arylaldehyde 13 to react to provide theX-substituted dialkoxyl arylphosphonate monomer 14. Step h may generallyresult in a X-substituted dialkoxyl arylphosphonate 14 having astructure of Formula II:

where each R^(1b) and R^(2b) can, independently, be C₁-C₂₀ alkyl, C₂-C₂₀alkene, C₂-C₂₀ alkyne, or alkylene glycol, each R³ and R⁴ can,independently, be C₁-C₂₀ alkyl, and X can be, for example, hydroxide,alkoxide, astatine, iodine, bromine, chlorine, or fluorine, triflate(CF₃SO₃ ⁻), mesylate (CH₃SO₃ ⁻), tosylate (CH₃C₆H₄SO₂ ⁻), or besylate(C₆H₅SO₃ ⁻).

In particular embodiments, contacting the phosphonate-containingcompound and the X-substituted dialkoxyl arylaldehyde 13 may includevarious additional steps such as, for example, placing the X-substituteddialkoxyl arylaldehyde 13 under conditions that allow the X-substituteddialkoxyl arylaldehyde 13 to be reduced to provide a X-substituteddialkoxyl arylmethanol; combining the X-substituted dialkoxylarylmethanol with a leaving group containing compound; contacting theleaving group containing compound with the X-substituted dialkoxylarylmethanol under conditions that allow the leaving group containingcompound with the X-substituted dialkoxyl arylmethanol to provide aX-substituted dialkoxyl arylmethyl-leaving group; contacting theX-substituted dialkoxyl arylmethyl-leaving group with a phosphitecontaining compound under conditions that allow the X-substituteddialkoxyl arylmethyl-leaving group with a phosphite containing compoundto react; and allowing an Arbuzov rearrangement to occur to provide theX-substituted dialkoxyl arylphosphonate 14 monomer. In various suchembodiments, the leaving group can be, for example, hydroxide, alkoxide,astatine, iodine, bromine, chlorine, or fluorine, triflate (CF₃SO₃ ⁻),tosylate (CH₃C₆H₄SO₂ ⁻), or besylate (C₆H₅SO₃ ⁻), or the like andcombinations thereof, and in particular embodiments, the leaving groupmay be mesylate (CH₃SO₃ ⁻). In some embodiments, the Arbuzovrearrangement can be carried out with a metal halide catalyst such as,for example, sodium iodide (NaI). This reaction can be done neat intriethylphosphite to drive the equilibrium towards formation of productsand to reduce hazardous waste streams; residual leftover “solvent” canbe vacuum stripped away and used for another batch.

Following preparation of the silyl containing monomeric unit,intermediate 7, and the phosphonate containing monomeric unit,intermediate 14, can be coupled to produce a X-substituted silylalkynyldiarylethene 15. In such embodiments, the method may include the stepsof combining the silylalkynyl arylaldehyde 7 and the X-substitutedarylphosphonate 14 and contacting the silylalkynyl arylaldehyde 7 andthe X-substituted arylphosphonate 14 under conditions that allow thesilylalkynyl arylaldehyde 7 and the X-substituted arylphosphonate 14 toreact to create a X-substituted silylalkynyl diarylethene 15. Inparticular embodiments, the conditions under which the silylalkynylarylaldehyde 7 and the X-substituted arylphosphonate 14 are combined toreact comprises a Horner-Wadsworth-Emmons coupling. In some embodiments,the Horner-Wadsworth-Emmons coupling between intermediates 7 and 14 canbe carried out using sodium hydride (NaH) in tetrahydrofuran (THF), andproduces intermediate 15 in quantitative yield. Notably, theHorner-Wadsworth-Emmons coupling typically forms alkenes in exclusivelythe trans configuration.

Finally, a regioregular aryl ethynyl-aryl vinyl copolymer 16 can beproduced by coupling X-substituted silylalkynyl diarylethenes 15. Incertain embodiments, the coupling X-substituted silylalkynyldiarylethenes 15 may be carried out by placing the X-substitutedsilylalkynyl diarylethene 15 under conditions that allow the silyl to beremoved to provide X-substituted alkynyl diarylethene 15 and contactingthe X-substituted diarylethene alkynyl diarylethene 15 under conditionsthat allow the X-substituted diarylethene alkynyl diarylethene 15 to becoupled to provide a regioregular poly(aryl ethynyl)-poly(aryl vinyl)16. In certain embodiments, the coupling of X-substituted alkynyldiarylethene diarylethene 15 can be carried out under conditions thatallow the X-substituted diarylethene alkynyl diarylethene 15 to becoupled by a Sonogashira coupling. In particular embodiments, couplingX-substituted silylalkynyl diarylethenes 15 may be carried out with oneequivalent of tetra-n-butyl ammonium fluoride (TBAF) in THF at roomtemperature. The fluoride ions produced under these conditions allow forthe removal of the alkyne protecting group leaving a base alkyne andgives the monoethynyl monoiodo monomer. The Sonogashira coupling maygenerally avoid homo-coupled byproducts between two alkyne groups, whichwould introduce regiorandomness via diyne defects and results in theregioregular poly(aryl ethynyl)-poly(aryl vinyl) 16. The Sonogashiracouplings can result in regioregular poly(aryl ethynyl)-poly(aryl vinyl)16 having about 100 repeating units, which is well above the thresholdof saturation for optical properties in these polymers.

The reaction described above allows for side chains having a widevariety of properties that will allow for the production of a widevariety of polymers having various characteristics of a fullyregioregular polymer.

EXAMPLES Example 1 Synthesis of2-methoxy-5-ethoxy-4-((tri-iso-propylsilyl)ethynyl)benzaldehyde

Hydroquinone can be added to a solution of sodium hydride (NaH)dissolved in tetrahydrofuran (THF) and combined with ethyl bromideyielding para-ethoxyphenol. The para-ethoxyphenol can be extracted andadded to a solution of tosyl chloride (TsCl) dissolved in pyridine andtetrahydrofuran (THF) at room temperature, yieldingpara-ethoxytosyloxybenzene. The para-ethoxytosyloxybenzene can beextracted and added to a solution of diatomic iodine (I₂) and potassiumiodide trioxide (KIO₃) dissolved in sulfuric acid (H₂SO₄) and aceticacid (CH₃COOH) yielding 4-ethoxy-3-iodo-1-tosyloxybenzene. The4-ethoxy-3-iodo-1-tosyloxybenzene is extracted and added to a solutionof aqueous sodium hydroxide (NaOH) and tert-butanol, removing thetosylate protecting group and yielding 4-ethoxy-3-iodophenol. The4-ethoxy-3-iodophenol can be extracted and exposed to resin-boundtriphenylphosphine (PPh₃) in a solution of azopyridine and methanol(CH₃OH) in a salt bath at 0° C., yielding 4-ethoxy-3-iodomethoxybenzene.The 4-ethoxy-3-iodomethoxybenzene can be extracted and added to asolution of titanium tetrachloride (TiCl₄) and 1,1-dichlorodimethylether(CHCl₂OCH₃) dissolved in dichloromethane (CH₂Cl₂) in a salt bath at −10°C., yielding 2-methoxy-4-iodo-5-ethoxybenzaldehyde. The2-methoxy-4-iodo-5-ethoxybenzaldehyde can be extracted and half of theyield can be added to tri-iso-propylsilylacetylene (TIPS-acetylene) inan amine solvent such as triethylamine, diethylamine, piperidine, ordi-iso-propylethylamine. This mixture can be passed over a palladium(Pd) catalyst bed, yielding2-methoxy-5-ethoxy-4-((tri-iso-propylsilyl)ethynyebenzaldehyde.

Example 2 Synthesis of diethyl2-ethoxy-4-iodo-5-methoxybenzylphosphonate

Hydroquinone can be added to a solution of sodium hydride (NaH)dissolved in tetrahydrofuran (THF) and combined with methyl bromideyielding para-methoxyphenol. The para-methoxyphenol can be extracted andadded to a solution of tosyl chloride (TsCl) dissolved in pyridine andtetrahydrofuran (THF) at room temperature, yieldingpara-methoxytosyloxybenzene. The para-methoxytosyloxybenzene can beextracted and added to a solution of diatomic iodine (I₂) and potassiumiodide trioxide (KIO₃) dissolved in sulfuric acid (H₂SO₄) and aceticacid (CH₃COOH) yielding 4-methoxy-3-iodo-1-tosyloxybenzene. The4-methoxy-3-iodo-1-tosyloxybenzene can be extracted and added to asolution of aqueous sodium hydroxide (NaOH) and tert-butanol, removingthe tosylate protecting group and yielding 4-methoxy-3-iodophenol. The4-methoxy-3-iodophenol can be extracted and exposed to resin-boundtriphenylphosphine (PPh₃) in a solution of azopyridine and ethanol(CH₃CH₂OH) in a salt bath at 0° C., yielding4-ethoxy-2-iodomethoxybenzene. The 4-ethoxy-2-iodomethoxybenzene can beextracted and added to a solution of titanium tetrachloride (TiCl₄) and1,1-dichlorodimethylether (CHCl₂OCH₃) dissolved in dichloromethane(CH₂Cl₂) in a salt bath at −10° C., yielding2-ethoxy-4-iodo-5-methoxybenzaldehyde. The2-ethoxy-4-iodo-5-methoxybenzaldehyde can be added to lithium aluminumhydride (LiAlH₄) and methanesulfonyl chloride (CH₃SO₂Cl) dissolved inpyridine, and then sodium iodide (NaI) and triethyl phosphite(P(OCH₂CH₃)₃) can be added to the reaction mixture, yielding diethyl2-ethoxy-4-iodo-5-methoxybenzylphosphonate.

Example 3 Synthesis of(E)-(4-(2-ethoxy-4-iodo-5-methoxystyryl)-(2-ethoxy-5-ethylphenyl)ethynyl)tri-iso-propylsilane

The 2-methoxy-5-ethoxy-4-((tri-iso-propylsilyl)ethynyl)benzaldehyde anddiethyl 2-ethoxy-4-iodo-5-methoxybenzylphosphonate can be added to asolution containing sodium hydride (NaH) dissolved in tetrahydrofuran(THF), yielding(E)-(4-(2-ethoxy-4-iodo-5-methoxystyryl)-(2-ethoxy-5-methylphenyl)ethynyl)tri-iso-propylsilane.

The(E)-((4-(2-ethoxy-4-iodo-5-methoxystyryl)-(2-ethoxy-5-methylphenyl)ethynyetri-iso-propylsilane(E)-(4-(2-ethoxy-4-iodo-5-methoxystyryl)-(2-ethoxy-5-methylphenyl)ethynyl)tri-iso-propylsilanecan be extracted and added to a solution of tetra-n-butylammoniumfluoride (TBAF) dissolved in tetrahydrofuran (THF) over a palladiumcatalyst bed, catalyzing a polymerization reaction yielding regioregularpoly(aryl ethynyl)-poly(aryl vinyl) (PPVE). A small sample of PPVE canbe added to a NMR tube containing a solution of 99.9% deuteratedchloroform (CDCl₃) and 0.1% tetramethylsilane (TMS). The dissolved PPVEcan then be inserted into a proton (¹H) NMR spectrometer and undergoanalysis to verify the purity and integrity of the resultant compound.The PPVE is expected to exhibit two aromatic peaks and one alkene peakin its NMR spectra.

One skilled in the art will appreciate that, for this and otherprocesses and methods disclosed herein, the functions performed in theprocesses and methods may be implemented in differing order.Furthermore, the outlined steps and operations are only provided asexamples, and some of the steps and operations may be optional, combinedinto fewer steps and operations, or expanded into additional steps andoperations without detracting from the essence of the disclosedembodiments.

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its spirit and scope, as will be apparentto those skilled in the art. Functionally equivalent methods andapparatuses within the scope of the disclosure, in addition to thoseenumerated herein, will be apparent to those skilled in the art from theforegoing descriptions. Such modifications and variations are intendedto fall within the scope of the appended claims. The present disclosureis to be limited only by the terms of the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isto be understood that this disclosure is not limited to particularmethods, reagents, compounds, compositions or biological systems, whichcan, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular embodiments onlyand is not intended to be limiting.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseof one having skill in the art would understand the convention (e.g., “asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). In those instances where a convention analogous to “atleast one of A, B, or C, etc.” is used, in general, such a constructionis intended in the sense of one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, or C” wouldinclude but not be limited to systems that have A alone, B alone, Calone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art, all languagesuch as “up to,” “at least,” and the like include the number recited andrefer to ranges which can be subsequently broken down into subranges, asdiscussed above. Finally, as will be understood by one skilled in theart, a range includes each individual member. Thus, for example, a grouphaving 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, agroup having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells,and so forth.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. A compound of general Formula III:

wherein: each R^(1a), R^(1b), R^(2a), and R^(2b) is, independently,C₁-C₂₀ alkyl, C₂-C₂₀ alkene, C₂-C₂₀ alkyne, or alkylene glycol; and X ishydroxide, alkoxide, astatine, iodine, bromine, chlorine, or fluorine,triflate(CF₃SO₃), mesylate (CH₃SO₃), tosylate (CH₃C₆H₄SO₂), or besylate(C₆H₅SO₃ ⁻).
 2. The compound according to claim 1, wherein each ofR^(1a) and R^(2a) is independently C₁-C₂₀ alkyl.
 3. The compoundaccording to claim 1, wherein each of R^(1a) and R^(2a) is independentlyC₁-C₆ alkyl.
 4. The compound according to claim 1, wherein each ofR^(1b) and R^(2b) is independently C₁-C₂₀ alkyl.
 5. The compoundaccording to claim 1, wherein each of R^(1b) and R^(2b) is independentlyC₁-C₆ alkyl.
 6. The compound according to claim 1, wherein X is iodine,bromine, chlorine, or fluorine.
 7. The compound according to claim 1,wherein R^(1a) is ethyl.
 8. The compound according to claim 1, whereinR^(2a) is methyl.
 9. The compound according to claim 1, wherein R^(1b)is ethyl.
 10. The compound according to claim 1, wherein R^(2b) ismethyl.
 11. The compound according to claim 1, wherein X is iodine. 12.The compound according to claim 1, wherein the compound is(E)-(4-(2-ethoxy-4-iodo-5-methoxystyryl)-(2-ethoxy-5-methoxyphenyl)ethynyl)tri-iso-propylsilane: